{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{6}{c}}
\hline\hline
          &\multicolumn{1}{c}{(1)}         &\multicolumn{1}{c}{(2)}         &\multicolumn{1}{c}{(3)}         &\multicolumn{1}{c}{(4)}         &\multicolumn{1}{c}{(5)}         &\multicolumn{1}{c}{(6)}         \\
\hline
ST        &   -0.110\sym{*}  &   -0.188\sym{**} &   -0.132\sym{**} &   -0.192         &    0.036         &    0.002         \\
          &  (0.056)         &  (0.084)         &  (0.065)         &  (0.148)         &  (0.117)         &  (0.139)         \\
\hline
\(N\)     &    19498         &    21901         &    13169         &    11472         &     6460         &     7007         \\
\(R^{2}\) &    0.045         &    0.043         &    0.051         &    0.053         &    0.049         &    0.053         \\
\hline\hline
\end{tabular}
}
